Temperature Constraints

Question 1

What are limiting factors?

Answer 1

Environmental conditions that limit the growth, abundance, and distribution of organisms
Organisms experience physiological stress at niche margins, along a limiting factor

Question 2

What is the law of tolerance?

Answer 2

Species have optimal survival conditions within environmental thresholds
Beyond this range, the rate of survival decreases

Question 3

What is a macroclimate?

Answer 3

Large-scale climate patterns that prevail over entire regions
Determined by climate cells and topography

Question 4

What is a microclimate?

Answer 4

Small-scale climate patterns at an area
Can deviate from macroclimate patterns
Determined by landscape, vegetation or small-scale topography features, such as elevation, mountain aspect, vegetation, etc

Question 5

How does elevation influence microclimate?

Answer 5

Timberline on a mountain reflects a shift in microclimate
The temp decreases at higher elevations but trees need a certain temp to grow

Question 6

How does aspect influence microclimate (north)?

Answer 6

Slopes exposed to the north receive less solar radiation, higher snow loads, and hence more water
Water availability = good for forest to grow

Question 7

How does aspect influence microclimate (south)?

Answer 7

Slopes exposed to the south receive more solar radiation, lower snow loads, and hence less water
Water availability = bad for forest growth so grasses and shrubs prevail

Question 8

How does vegetation influence microclimate?

Answer 8

By casting shade
In the understory, temps are cooler and evaporation is decreased

Question 9

How does surface colour influence microclimate?

Answer 9

Lighter colours = reflect light, surroundings don’t increase in temp
Darker colours = absorb light, surroundings increase in temp

Question 10

What is albedo?

Answer 10

The reflectivity of a landscape
How much light is reflected and does not get absorbed
Lighter = higher albedo

Question 11

How do boulders and burrows influence microclimate?

Answer 11

Some organisms live under rocks or in burrows
They create shade and allow inhabiting animals to avoid heat

Question 12

What are temperatures like in aquatic environments?

Answer 12

Water temperatures fluctuate much less than air temperatures on land
Only fluctuate between -4 to 32°

Question 13

Why is water temperature stable?

Answer 13

Water has an higher capacity for absorbing heat energy without changing temperature than air
Heat is absorbed by water as it evaporates
Water gives up heat energy as it freezes

Question 14

What is thawing and vaporization?

Answer 14

Energy absorbed as heat is supplied
Leads to intermittent, stable temperatures along a heat gradient

Question 15

What is the range of tolerance in plants (temperature)?

Answer 15

Limiting factor of photosynthesis

Question 16

What are evolutionary tradeoffs?

Answer 16

Adapting to one set of environmental conditions generally reduces fitness in other environments

Question 17

What strategies do organisms have to deal with temp constraints?

Answer 17

Die
Migrate
Acclimate
Adapt

Question 18

How do organisms cope with extreme temps with death?

Answer 18

Avoiding extreme temps by maximizing reproduction, followed by death
-annual plants

Question 19

How do organisms cope with extreme temps with migration?

Answer 19

Avoiding extreme temps by migrating to distant regions
-birds

Question 20

How do organisms cope with extreme temps with acclimatization?

Answer 20

Physiological or morphological changes in response to changes in the environment
-adjustment to elevation

Question 21

What is the difference between acclimatization and adaptation?

Answer 21

Acclimatization is reversible and adaptation is not due to genetics

Question 22

How do organisms cope with extreme temps with adaptation?

Answer 22

Hibernation
Estivation
Freeze tolerance
Thick fur, fat, short body appendages

Question 23

What is the heat balance equation?

Answer 23

Hs=Hm±Hcd±Hcv±Hr-He

Question 24

How have plants adapted to cold temps?

Answer 24

Dark coloured leaves
Cushion growth form
Leaf and flower orientation
Smaller surface-area ratio

Question 25

How do plants adapted to cold temps increased heat gain and decrease heat loss?

Answer 25

Increase heat gain from Hr and Hcd
Decrease heat loss from Hcv

Question 26

How have plants adapted to hot temps?

Answer 26

Decrease contact with the ground
Open growth form
Reduced leaves
Light surfaces like hairs

Question 27

How do plants adapted to hot temps increase heat loss and decrease heat gain?

Answer 27

Increase heat loss from Hcv
Decrease heat gain from Hcd and Hr

Question 28

How do poikilotherms regulate body temperature?

Answer 28

Body temperature varies with environment

Question 29

How do homeotherms regulate body temperature?

Answer 29

Body temp remains relatively constant regardless of environment

Question 30

How do ectotherms regulate body temperature?

Answer 30

Control body temp using external energy
Cold? get in sun
Hot? get out of sun

Question 31

How do endotherms regulate body temperature?

Answer 31

Control body temp using internal energy
Uses energy from metabolism
Cold? shivering generates heat
Hot? sweating and panting cools

Question 32

Why be endothermic?

Answer 32

Allows organisms to live in environments where the average temp is lower than their body temp